Synthesis of hierarchical Mn3O4 nanowires on reduced graphene oxide nanoarchitecture as effective pseudocapacitive electrodes for capacitive desalination application

Abstract

We present a hierarchical network architecture fabrication of pseudocapacitive Mn3O4 nanowires immobilized on reduced graphene oxide (Mn3O4/RGO) hybrids for effective capacitive deionization (CDI). A hydrothermal synthesis process was employed for constructing Mn3O4/RGO nanoarchitecture with hierarchical pores to ease the interaction with salt ions. Physico-chemical analysis verified the Mn3O4 nanowires with few microns sized length and diameter of 20–30 nm were evenly immobilized on the surfaces of the RGO. With this tailored nanoarchitecture, the Mn3O4/RGO based electrode shows ideal pseudocapacitive behavior with a higher capacitance of (Cs) of 437 F g−1, the energy density of 41.12 Wh kg−1 and power density of 400 W kg−1 at 1 A g−1 in 1 M NaCl solution. Benefiting from the fascinating electrochemical features, the Mn3O4/RGO nanoarchitecture constructed CDI electrode exhibited high electrosorption capacity (SAC) of 34.5 mg g−1 at 1.2 V with a high salt adsorption rate (ASAR) of 1.15 mg g−1 min−1 in 1000 mg L−1 NaCl solution. The much improved SAC, ASAR, and recyclability could be attributed to the distinctive pseudocapacitive nanoarchitecture, which improves the sodiation/desodiation. The present investigation indicates that the Mn3O4/RGO nanoarchitecture is a capable CDI electrode material for desalination application.